Just a little information. With much help from this group I got my Non immigrant O-A visa from the Royal Thai Embassy UK.
Emirates business class flights jumped from approx ยฃ2200 to ยฃ3500 and so I flew with Eva Air (excellent)
However the check in desk attendant checked my return date (30th May) and asked if I had a visa. I replied in the affirmative but off she went to have it checked with a supervisor. All in order she said, we are obliged to check she told me. All with the greatest of civility.
TLDR : Answer Summary
The poster shares their successful experience obtaining a Non-Immigrant O-A visa from the Royal Thai Embassy in the UK, mentioning a flight choice due to high prices with Emirates. They recount a check-in process at the airport where an attendant verified their visa before allowing them to proceed, emphasizing the importance of proper visa checks.